This invention relates to absorbent articles or devices. In a preferred embodiment, the present invention relates to an improved absorbent device that is worn interlabially by female wearers for catamenial purposes, incontinence protection, or both. The improved absorbent device has a substance on its body-contacting surface to assist the device in staying in place against the wearer""s body.
All manner and variety of absorbent articles configured for the absorption of body fluids such as menses, urine and feces are well known. With respect to feminine protection devices, the art has offered two basic types; sanitary napkins have been developed for external wear about the pudendal region while tampons have been developed for internal wear within the vaginal cavity for interruption of menstrual flow therefrom. Such tampon devices are disclosed in U.S. Pat. No. 4,412,833, entitled xe2x80x9cTampon Applicatorxe2x80x9d, issued to Weigner, et al. on Nov. 1, 1983, and U.S. Pat. No. 4,413,986, entitled xe2x80x9cTampon Assembly With Means For Sterile Insertionxe2x80x9d, issued to Jacobs on Nov. 8, 1983.
Hybrid devices which attempt to merge the structural features of the sanitary napkins and the tampons into a single device have also been proposed. Such hybrid devices are disclosed in U.S. Pat. No. 2,092,346, entitled xe2x80x9cCatamenial Padxe2x80x9d, issued to Arone on Sep. 7, 1937, and U.S. Pat. No. 3,905,372, entitled xe2x80x9cFeminine Hygiene Protective Shieldxe2x80x9d, issued to Denkinger on Sep. 16, 1975. Other less intrusive hybrid devices are known as labial or interlabial sanitary napkins and are characterized by having a portion which at least partially resides within the wearer""s vestibule and a portion which at least partially resides external of the wearer""s vestibule. Such devices are disclosed in U.S. Pat. No. 2,662,527, entitled xe2x80x9cSanitary Padxe2x80x9d, issued to Jacks on Dec. 15, 1953, and U.S. Pat. No. 4,631,062, entitled xe2x80x9cLabial Sanitary Padxe2x80x9d, issued to Lassen, et al. on Dec. 23, 1986.
Interlabial pads have the potential to provide even greater freedom from inconvenience because of their small size and reduced risk of leakage. Numerous attempts have been made in the past to produce absorbent devices which would combine the best features of tampons and sanitary napkins while avoiding at least some of the disadvantages associated with each of these types of devices. Examples of such devices are described in U.S. Pat. No. 2,917,049 issued to Delaney on Dec. 15, 1959, U.S. Pat. No. 3,420,235 issued to Harmon on Jan. 7, 1969, U.S. Pat. No. 4,595,392 issued to Johnson, et al. on Jun. 17, 1986, and U.S. Pat. No. 5,484,429 issued to Vukos, et al. on Jan. 16, 1996. A commercially available interlabial device is the INSYNC MINIFORM interlabial pad which is marketed by A-Fem of Portland, Oreg. and described in U.S. Pat. Nos. 3,983,873 and 4,175,561 issued to Hirschman on Oct. 5, 1976 and Nov. 27, 1979, respectively.
Many of these devices have not met with great commercial success, however. There are drawbacks associated with all of the above products. For example, the device described in the Delaney patent does not appear to be capable of an easy and comfortable insertion, due to the possibility of the layers of absorbent material opening up during insertion. The commercially available IN-SYNC interlabial device suffers from the disadvantage that it may tend to allow by-pass flow around its edges. Such flow can cause body soiling or panty soiling which many consumers find unacceptable. Additionally, previously known interlabial devices such as the INSYNC Miniform interlabial pad may not reliably cover the urethra and/or the vaginal introitus during all body movements (e.g. when the wearer is squatting). Such products may also not be reliably expelled when the wearer urinates. Further, such an interlabial pad may not have sufficient absorbent capacity for use during a wearer""s menstrual period, and/or may fall out of the interlabial space when fully loaded. In order to handle the wearer""s menstrual flow, a user may have to wear the interlabial pad in combination with a sanitary napkin.
Therefore, a need exists for an improved interlabial device which will reduce the incidence of body and panty soiling when used. Such a device should be easy to insert and be comfortable during wear. A need exists for an interlabial device which also covers the walls of the wearer""s labia throughout a range of body motions and reliably covers the vaginal introitus and preferably also the urethra during such motions. A need also exists for an improved interlabial device which has sufficient capacity to serve as a stand alone protection function during the heavy flow days of a wearer""s menstrual period, and is not subject to the problem of falling out of the interlabial space when loaded to its absorbent capacity. A need also exists for an improved absorbent interlabial device which may be used as part of a system of feminine hygiene protection or with a feminine hygiene kit.
The present invention relates to absorbent devices such as sanitary napkins, pantiliners, interlabial devices, and incontinence devices. In a preferred embodiment, the present invention relates to an improved absorbent device that is insertable into the interlabial space of a female wearer for catamenial purposes (including menses and mid-cycle discharges), incontinence protection (including urine), or both. The absorbent interlabial device has at least one body-contacting surface which comprises a substance that contacts the wearer""s body for assisting the interlabial device in staying in place in the desired position in the interlabial space. The substance can be either adhesive or non-adhesive. In embodiments in which the substance is non-adhesive, it may have no initial tack so that it will not stick to the wrong portions of the wearer""s body when the device is placed between the labia. Non-adhesive substances include moisture-activated substances which become viscous and develop a tack when contacted by relatively small amounts of moisture.
Preferably, the substance should adhere the interlabial device to the inside surfaces of the labia minora, or alternatively to the labia majora or both the labia minora and labia majora so that it remains adhered to these surfaces (on both sides of the interlabial space) when the wearer moves in a way that the labia spread (e.g., when the wearer squats). This will allow the interlabial device to remain in place during wearing conditions, and will also ensure that it is contacted by a stream of urine when the wearer urinates so that it will be removed on urination. The need for such a substance becomes more important as the loading that the interlabial device is expected to hold (that is, the weight of absorbed bodily liquids) increases. Typically, the unloaded interlabial device will weigh less than or equal to about 5 grams. As the weight of absorbed bodily liquids increases, the force of gravity on the loaded interlabial device increases. This results in the need for increased ability to hold the interlabial device in place, particularly when the exudate loading is greater than or equal to about 8 grams.
Moisture-activated substances are particularly preferred for use with the interlabial device because they can make the interlabial device easier to apply than pressure sensitive or tacky adhesive-coated devices. They are also particularly useful for sealing against this portion of the wearer""s body since moisture is naturally present. Some particularly preferred moisture-activated substances are polyethylene glycols (xe2x80x9cPEGsxe2x80x9d), sodium carboxymethylcellulose, cellulose gums, hydroxyethyl celluloses, hydroxypropyl celluloses, hydroxypropylmethyl celluloses, functionalized guars (such as cationic guar and hydroxypropyl guar), carrageenan, glycols (dihydric alcohols) such as propylene glycols, hexylene glycols, polyols which contain three or more hydroxyl groups such as glycerin, surfactants such as polyoxyl alkylates (polyoxyethylene sterates) ethoxylated alcohols, sugar surfactants, sugars (such as glucose, fructose, and sucrose), alone or in combination with pectin, guar gum, and other gums.
Polyethylene glycols are particularly preferred for several reasons. Some of the higher molecular weight polyethylene glycols are typically solids that are capable of dissolving in water. They can be easily applied to the interlabial device. Polyethylene glycols can be applied to the body-contacting surface of the interlabial device using any conventional processing steps, which are described in greater detail below. Once applied, they will typically dry to a non-tacky solid, preferably a powder form. This is preferable since it is desirable that the substance does not form an occlusive film over the body-contacting surface of the interlabial device. Polyethylene glycols, since they are very water soluble, are also capable of losing their tendency to stick to the labia when the wearer urinates, so the interlabial device will be expelled by urination as intended. Their water solubility also ensures that they will not interfere with the ability of flushable interlabial devices to flush down a toilet, and will not float in the toilet as some other products. (The tendency for other products to float results in an extremely inconvenient situation for users who have to remove such products from the toilet bowl, and then dispose of these products.) Polyethylene glycols are also biodegradable, unlike most pressure sensitive adhesives, which are silicone-based.
These materials may also be mixed into lotion (emollient) compositions, wherein the lotion provides lubricity during the insertion process and the moisture-activated substance in the lotion will cause the composition to develop a tack when contacted by the moist labial tissues. In such a composition, the lotion or emollient can serve as a carrier for the particulate material.
The absorbent interlabial device, in one embodiment, is a small pad-like structure that comprises a liquid pervious topsheet, a liquid impervious backsheet which is joined to the topsheet, and an absorbent core positioned between the topsheet and backsheet. The device preferably comprises an axis of preferred bending, preferably located generally along the longitudinal centerline of the device. When the device is folded along this axis and inserted into the wearer""s interlabial space, the topsheet maintains contact with the walls of the wearer""s labia. Preferably, the liquid pervious topsheet is constructed of rayon or needle punched rayon. The absorbent core is preferably also constructed of rayon, cotton, or a blend of rayon and cotton. Preferably, the device comprises biodegradable materials. In particularly preferred embodiments, the backsheet of the absorbent interlabial device is water dispersible. A tab may be joined to the backsheet of the device to facilitate insertion and optional removal of the device with the fingers.
In alternative embodiments, the absorbent interlabial device may utilize adhesive substances. For example, in one embodiment, the absorbent interlabial device has a longitudinal centerline oriented in the same direction as a wearer""s vaginal opening, a longitudinal central region along the longitudinal centerline, and a pair of longitudinal side regions laterally outboard of the longitudinal centerline. In this embodiment, the absorbent interlabial device comprises a pressure sensitive adhesive on the body-contacting surface on the longitudinal side regions of the interlabial device, so that the pressure sensitive adhesive does not block or retard, but permits urine to flow into the interlabial device from the wearer""s urethra.